1. Steel
The steel used on the Pioneer is X39Cr13.
Nice review - great pics.
Be grateful for any references to the steel used, please?
According to Wikipedia Swiss Army Knife (section: Applied Materials)
The martensitic stainless steel alloy used for the cutting blades is optimized for high toughness and corrosion resistance and has a composition of 15% chromium, 0.60% silicon, 0.52% carbon, 0.50% molybdenum, and 0.45% manganese and is designated X55CrMo14 or 1.4110 according to Victorinox. After a hardening process at 1040 °C and annealing at 160 °C the blades achieve an average blade steel hardness of 56 HRC. This steel hardness is suitable for practical use and easy resharpening, but less than achieved in stainless steel alloys used for blades optimized for high wear resistance.[16][17][18]
According to Victorinox the martensitic stainless steel alloy used for the parts is X39Cr13 or 1.4031 and for the springs X20Cr13 or 1.4021.[19]
X39Cr13 is used for parts,
but not for the blade steel which is supposed to be X55CrMo14 or 1.4110.
Please also see: Victorinox Steel
As others may have mentioned the Pioneer was regarded as the civilian version of the old Solider model with addition of a split keyring.
Older Soldier model shown with a Farmer (which was in the "Pioneer series") note the difference in Swiss shields:

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Vincent
http://picasaweb.com/UnknownVincent?showall=true
http://UnknownVincent.Shutterfly.com
http://UnknownVT.Shutterfly.com
http://UnknownVT.multiply.com/photos